Dual servo stage without mechanical coupling for process of manufacture and inspection of flat panel displays via modular design approach

Abstract

In micromanufacturing and nanomanufacturing in the semiconductor and flat panel display industry, many kinds of positioning system that have a large working area, high speed, and high accuracy are required. In this paper, the design of a mechanically decoupled dual servo (MDDS) stage is proposed and presented. The stage consists of a coarse stage actuated by a linear motor and a fine stage actuated by a voice coil motor. The two stages are required to be developed independently, if possible, to save lead time and ensure the security of trade secrets; therefore, the MDDS stage is designed according to a modular design approach. A dual servo tracking controller is introduced for the MDDS by appending a fine controller to a conventional coarse controller. Despite the modular design without mechanical coupling, a reaction force between the fine stage and coarse stage is generated by the magnetic coupling that is detrimental to positioning and tracking. Therefore, a simple compensator that reduces the effect of the reaction force is also presented. Simulations and experiments are performed to evaluate the performance of the MDDS stage.